Material for organic electroluminescence devices and organic electroluminescence device using the material

ABSTRACT

A material for organic electroluminescence devices comprising a compound in which a heterocyclic group having nitrogen is bonded to an arylcarbazolyl group or a carbazolylalkylene group and an organic electroluminescence device comprising an anode, a cathode and an organic thin film layer comprising at least one layer and disposed between the anode and the cathode, wherein at least one layer in the organic thin film layer comprises the material for organic electroluminescence devices described above. The material can provide an organic electro-luminescence device emitting bluish light with a high purity of color. The organic electroluminescence device uses the material.

This application is a continuation application of U.S. patentapplication Ser. No. 10/393,988 filed on Mar. 24, 2003 (now abandoned)and claims priority to Japanese Application Nos. 2002-081234 filed onMar. 22, 2002 and 2002-299810 filed on Oct. 15, 2002, the entirecontents of each of the above are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a material for organicelectro-luminescence devices (organic EL devices) and an organic ELdevice using the material and, more particularly, to an organic ELdevice emitting bluish light with a high purity of color.

BACKGROUND ART

Organic EL devices which utilize organic substances are expected to beuseful for application as an inexpensive full color display device ofthe solid light emission type having a great size and variousdevelopments on the organic EL devices are being conducted. In general,an organic EL device has a construction comprising a light emittinglayer and a pair of electrodes disposed at both sides of the lightemitting layer.

The light emission of the organic EL device is a phenomenon in which,when an electric field is applied between the two electrodes, electronsare injected from the cathode side and holes are injected from the anodeside, the electrons are recombined with the holes in the light emittinglayer to form an excited state, and energy generated when the excitedstate returns to the ground state is emitted as light.

As the light emitting material, chelate complexes such astris(8-quinolinolato)aluminum, coumarine derivatives,tetraphenylbutadiene derivatives, bisstyrylarylene derivatives andoxadiazole derivatives are known. It has been reported that these lightemitting materials emit light in the visible region of blue to red andit is expected that color display devices can be obtained by using theselight emitting materials (for example, Japanese Patent ApplicationLaid-Open Nos. Heisei 8(1996)-239655, and Heisei 7(1995)-138561.

Although the practical use of displays using organic EL devices recentlystarted, the full color display device is still under development. Inparticular, an organic EL device which emits bluish light with excellentpurity of color and efficiency of light emission has been desired.

As the device as the attempt to satisfy the above desire, for example, adevice using a phenylanthracene derivative as the material emitting bluelight is disclosed in Japanese Patent Application Laid-Open No. Heisei8(1996)-12600. The phenylanthracene derivative is used as the materialemitting blue light and, in general, used as a laminate composed of alayer of the material emitting blue light and a layer of a complex oftris(8-quinolinolato)aluminum (Alq). However, the efficiency of lightemission, the life and the purity of blue light are insufficient for thepractical application. In Japanese Patent Application Laid-Open No.2001-288462, a device emitting blue light in which an amine-basedaromatic compound is used for the light emitting layer is disclosed.However, the efficiency of light emission of this device is asinsufficient as 2 to 4 cd/A. In Japanese Patent Application Laid-OpenNo. 2001-160489, a device in which an azafluoranthene compound is addedto the light emitting layer is disclosed. However, this device emitslight of yellow to green and cannot emit blue light having asufficiently high purity of color.

DISCLOSURE OF THE INVENTION

The present invention is made to overcome the above problems and has anobject of providing a material for organic EL devices which emits bluishlight with excellent purity of color and an organic EL device utilizingthe material.

As the result of extensive studies by the present inventors, it wasfound that an organic EL device exhibiting excellent purity of bluecolor could be obtained by using a compound having a heterocyclic grouphaving nitrogen bonded to an arylcarbazolyl group or acarbazolylalkylene group as the host material. The present invention hasbeen completed based on this knowledge.

The present invention provides a material for organicelectroluminescence devices which comprises a compound represented byfollowing general formula (1) or (2):(Cz-)_(n)A   (1)Cz(-A)_(m)   (2)wherein Cz represents a substituted or unsubstituted arylcarbazolylgroup or carbazolylalkylene group, A represents a group represented byfollowing general formula (A):(M)_(p)-(L)_(q)-(M′)_(r)   (A)wherein M and M′ each independently represent a heteroaromatic ringhaving 2 to 40 carbon atoms and nitrogen atom and forming a substitutedor unsubstituted ring, M and M′ may represent a same ring or differentrings, L represents a single bond, a substituted or unsubstituted arylgroup or arylene group having 6 to 30 carbon atoms, a substituted orunsubstituted cycloalkylene group having 5 to 30 carbon atoms or asubstituted or unsubstituted heteroaromatic ring having 2 to 30 carbonatoms, p represents an integer of 0 to 2, q represents an integer of 1or 2, r represents an integer of 0 to 2, and p+r represents an integerof 1 or greater; and

-   n and m each represent an integer of 1 to 3.

The present invention also provides an organic electroluminescencedevice comprising an anode, a cathode and an organic thin film layercomprising at least one layer and disposed between the anode and thecathode, wherein at least one layer in the organic thin film layercomprises a material for organic electroluminescence devices describedabove. Among the above organic thin film layers, the light emittinglayer, the electron transporting layer or the hole transporting layermay comprise the above material for organic EL devices.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

The material for organic electroluminescence devices of the presentinvention comprises a compound represented by following general formula(1) or (2):(Cz-)_(n)A   (1)Cz(-A)_(m)   (2)

In the above formulae, Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylalkylene group and n and m eachrepresent an integer of 1 to 3.

It is preferable that the aryl group in the arylcarbazolyl group has 6to 30 carbon atoms. Examples of the aryl group include phenyl group,naphthyl group, anthryl group, phenanthryl group, naphthacenyl group,pyrenyl group, fluorenyl group, biphenyl group and terphenyl group.Among these groups, phenyl group, naphthyl group, biphenyl group andterphenyl group are preferable.

It is preferable that the alkylene group in the carbazolylalkylene grouphas 1 to 10 carbon atoms. Examples of the alkylene group includemethylene group, ethylene group, propylene group, isopropylene group,n-butylene group, s-butylene group, isobutylene group, t-butylene group,n-pentylene group, n-hexylene group, n-heptylene group, n-octylenegroup, hydroxymethylene group, chloromethylene group and aminomethylenegroup. Among these groups, methylene group, ethylene group, propylenegroup, isopropylene group, n-butylene group, t-butylene group andn-pentylene group are preferable.

In general formulae (1) and (2), A represents a group represented by thefollowing general formula (A):(M)_(p)-(L)_(q)-(M′)_(r)   (A)

M and M′ each independently represent a heteroaromatic ring having 2 to40 carbon atoms and nitrogen atom and forming a substituted orunsubstituted ring, and M and M′ may represent the same ring ordifferent rings.

Examples of the heteroaromatic ring having nitrogen atom include ringsof pyridine, pyrimidine, pyrazine, triazine, aziridine, azaindolidine,indolidine, imidazole, indole, isoindole, indazole, purine, puteridine,β-carboline, naphthylidine, quinoxaline, terpyridine, bipyridine,acridine, phenanthroline, phenazine and imidazopyridine. Among theserings, rings of pyridine, terpyridine, pyrimidine, imidazopyridine andtriazine are preferable.

L represents a single bond, a substituted or unsubstituted aryl group orarylene group having 6 to 30 carbon atoms, a substituted orunsubstituted cycloalkylene group having 5 to 30 carbon atoms or asubstituted or unsubstituted heteroaromatic ring having 2 to 30 carbonatoms.

p represents an integer of 0 to 2, q represents an integer of 1 or 2, rrepresents an integer of 0 to 2, and p+r represents an integer of 1 orgreater.

Examples of the aryl group having 6 to 30 carbon atoms include phenylgroup, biphenyl group, terphenyl group, naphthyl group, anthranyl group,phenanthryl group, pyrenyl group, chrysenyl group, fluoranthenyl groupand perfluoroaryl groups. Among these groups, phenyl group, biphenylgroups, terphenyl group and perfluoroaryl groups are preferable.

Examples of the arylene group having 6 to 30 carbon atoms includephenylene group, biphenylene group, terphenylene group, naphthylenegroup, anthranylene group, phenanthrylene group, pyrenylene group,chrysenylene group, fluoranthenylene group and perfluroarylene groups.Among these groups, phenylene group, biphenylene group, terphenylenegroup and perfluoroarylene groups are preferable.

Examples of the cycloalkylene group having 5 to 30 carbon atoms includecyclopentylene group, cyclohexylene group and cycloheptylene group.Among these groups, cyclohexylene group is preferable.

Examples of the heteroaromatic group having 2 to 30 carbon atoms include1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyradinyl group,2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 1-indolylgroup, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolylgroup, 6-indolyl group, 7-indolyl group, 1-isoindolyl group,2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolylgroup, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furylgroup, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group,5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group,1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranylgroup, 5-isobenzofuranyl group, 6-isobenzofuranyl group,7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolylgroup, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolylgroup, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group,5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group,8-isoquinolyl group, 2-quinoxanyl group, 5-quinoxanyl group,6-quinoxanyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolylgroup, 4-carbazolyl group, 9-carbazolyl group, 1-phenanthrydinyl group,2-phenanthrydinyl group, 3-phenanthrydinyl group, 4-phenanthrydinylgroup, 6-phenanthrydinyl group, 7-phenanthrydinyl group,8-phenanthrydinyl group, 9-phenanthrydinyl group, 10-phenanthrydinylgroup, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group,4-acridinyl group, 9-acridinyl group, 1,7-phenanthrolin-2-yl group,1,7-phenanthrolin-3-yl group, 1,7-phenanthrolin-4-yl group,1,7-phenanthrolin-5-yl group, 1,7-phenanthrolin-6-yl group,1,7-phenanthrolin-8-yl group, 1,7-phenanthrolin-9-yl group,1,7-phenanthrolin-10-yl group, 1,8-phenanthrolin-2-yl group,1,8-phenanthrolin-3-yl group, 1,8-phenanthrolin-4-yl group,1,8-phenanthrolin-5-yl group, 1,8-phenanthrolin-6-yl group,1,8-phenanthrolin-7-yl group, 1,8-phenanthrolin-9-yl group,1,8-phenanthrolin-10-yl group, 1,9-phenanthrolin-2-yl group,1,9-phenanthrolin-3-yl group, 1,9-phenanthrolin-4-yl group,1,9-phenanthrolin-5-yl group, 1,9-phenanthrolin-6-yl group,1,9-phenanthrolin-7-yl group, 1,9-phenanthrolin-8-yl group,1,9-phenanthrolin-10-yl group, 1,10-phenanthrolin-2-yl group,1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-4-yl group,1,10-phenanthrolin-5-yl group, 2,9-phenanthrolin-1-yl group,2,9-phenanthrolin-3-yl group, 2,9-phenanthrolin-4-yl group,2,9-phenanthrolin-5-yl group, 2,9-phenanthrolin-6-yl group,2,9-phenanthrolin-7-yl group, 2,9-phenanthrolin-8-yl group,2,9-phenanthrolin-10-yl group, 2,8-phenanthrolin-1-yl group,2,8-phenanthrolin-3-yl group, 2,8-phenanthrolin-4-yl group,2,8-phenanthrolin-5-yl group, 2,8-phenanthrolin-6-yl group,2,8-phenanthrolin-7-yl group, 2,8-phenanthrolin-9-yl group,2,8-phenanthrolin-10-yl group, 2,7-phenanthrolin-1-yl group,2,7-phenanthrolin-3-yl group, 2,7-phenanthrolin-4-yl group,2,7-phenanthrolin-5-yl group, 2,7-phenanthrolin-6-yl group,2,7-phenanthrolin-8-yl group, 2,7-phenanthrolin-9-yl group,2,7-phenanthrolin-10-yl group, 1-phenoxazinyl group, 2-phenoxazinylgroup, 1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinylgroup, 4-phenothiazinyl group, 10-phenothiaznyl group, 1-phenoxazinylgroup, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group,10-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolylgroup, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group,2-thienyl group, 3-thienyl group, 2-methylpyrrol-1-yl group,2-methylpyrrol-3-yl group, 2-methylpyrrol-4-yl group,2-methylpyrrol-5-yl group, 3-methylpyrrol-1-yl group,3-methylpyrrol-2-yl group, 3-methylpyrrol-4-yl group,3-methylpyrrol-5-yl group, 2-t-butylpyrrol-4-yl group,3-(2-phenylpropyl)pyrrol-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group and 4-t-butyl-3-indolyl group. Among thesegroups, pyridinyl group and quinolyl group are preferable.

Examples of the substituent in the group represented by Cz, M or M′ ingeneral formulae (1), (2) and (A) include halogen atoms such as chlorineatom, bromine atom and fluorine atom, carbazole group, hydroxyl group,substituted and unsubstituted amino groups, nitro group, cyano group,silyl group, trifluoromethyl group, carbonyl group, carboxyl group,substituted and unsubstituted alkyl groups, substituted andunsubstituted alkenyl groups, substituted and unsubstituted arylalkylgroups, substituted and unsubstituted aromatic groups, substituted andunsubstituted heteroaromatic heterocyclic groups, substituted andunsubstituted aralkyl groups, substituted and unsubstituted aryloxygroups and substituted and unsubstituted alkyloxyl groups. Among thesegroups, fluorine atom, methyl group, perfluorophenylene group, phenylgroup, naphthyl group, pyridyl group, pyrazyl group, pyrimidyl group,adamantyl group, benzyl group, cyano group and silyl group arepreferable.

The bonding mode of the compound represented by general formula (1) or(2) described above is shown in Table 1 in the following in accordancewith the numbers represented by n and m.

TABLE 1 n = m = 1 n = 2 n = 3 m = 2 m = 3 Cz—A Cz—A—Cz

A—Cz—A

The bonding mode of the group represented by general formula (A)described above is shown in Table 2 in the following in accordance withthe numbers represented by p, q and r.

TABLE 2 No p q r The bonding mode [1] 0 1 1 L—M′ [2] 0 1 2 L—M′ —M′, M′—L—M′ [3] 0 2 1 L—L—M′, L—M′ —L [4] 0 2 2 L—L—M′ —M′, M′ —L—L—M′,

[5] 1 1 0 The same as [1] except that M′ is replaced with M. [6] 1 1 1M—L—M′ [7] 1 1 2

[8] 1 2 0 The same as [3] except that M′ is replaced with M. [9] 1 2 1M—L—L—M′, L—M—L—M′, M—L—M′ —L [10] 1 2 2 M—L—L—M′ —M′, M′ —L—M—L—M′, M′—M′ —L—M—L,

[11] 2 1 0 The same as [2] except that M′ is replaced with M. [12] 2 1 1The same as [7] except that M′ is replaced with M and M is replaced withM′. [13] 2 1 2

[14] 2 2 0 The same as [4] except that M′ is replaced with M. [15] 2 2 1The same as [10] except that M′ is replaced with M and M is replacedwith M′. [16] 2 2 2 M—M—L—L—M′ —M′,

The group represented by Cz which is bonded to the group represented byA may be bonded to any of the groups represented by M, L or M′ ingeneral formula (A) representing the group represented by A.

For example, when the group represented by A has the bonding mode [6] inTable 2 (p=q=r=1) in the compound represented by Cz-A in which m=n=1 ingeneral formula (1) or (2), the bonding mode includes three bondingmodes of Cz-M-L-M′, M-L(Cz)-M′ and M-L-M′-Cz.

When the group represented by A has the bonding mode [7] in Table 2(p=q=1 and r=2) in the compound represented by Cz-A-Cz in which n=2 ingeneral formula (1), the bonding mode includes bonding modes shown inthe following:

With respect to the bonding mode of the group represented by generalformula (1), (2) or (A) and the combination of the groups shown in theabove as the examples, materials for organic EL devices comprisingcompounds shown in (i) to (iv) in the following are preferable.

(i) Materials for organic EL devices in which

n=1 in general formula (1) and p=1 and r=0 in general formula (A);

in general formula (1), Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylalkylene group; and

in general formula (A), M represents a heterocyclic six-membered orseven-membered ring having 4 or 5 carbon atoms and nitrogen atom andforming a substituted or unsubstituted ring, a heterocyclicfive-membered ring having 2 to 4 carbon atoms and nitrogen atom andforming a substituted or unsubstituted ring, a heterocyclic ring having8 to 11 carbon atoms and nitrogen atom and forming a substituted orunsubstituted ring or a substituted or unsubstituted imidazopyridinylring, and L represents a substituted or unsubstituted aryl group orarylene group having 6 to 30 carbon atoms or a substituted orunsubstituted heteroaromatic ring having 2 to 30 carbon atoms.

(ii) Materials for organic EL devices in which

n=2 in general formula (1) and p=1 and r=0 in general formula (A);

in general formula (1), Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylalkylene group; and

in general formula (A), M represents a heterocyclic six-membered orseven-membered ring having 4 or 5 carbon atoms and nitrogen atom andforming a substituted or unsubstituted ring, a heterocyclicfive-membered ring having 2 to 4 carbon atoms and nitrogen atom andforming a substituted or unsubstituted ring, a heterocyclic ring having8 to 11 carbon atoms and nitrogen atom and forming a substituted orunsubstituted ring or a substituted or unsubstituted imidazopyridinylring, and L represents a substituted or unsubstituted aryl group orarylene group having 6 to 30 carbon atoms or a substituted orunsubstituted heteroaromatic ring having 2 to 30 carbon atoms.

(iii) Materials for organic EL devices in which

n=1 in general formula (1) and p=2 and r=0 in general formula (A);

in general formula (1), Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylalkylene group; and

in general formula (A), M represents a heteroaromatic ring having 2 to40 carbon atoms and nitrogen atom and forming a substituted orunsubstituted ring, and L represents a substituted or unsubstituted arylgroup or arylene group having 6 to 30 carbon atoms or a substituted orunsubstituted heteroaromatic ring having 2 to 30 carbon atoms.

(iv) Materials for organic EL devices in which

m=2 in general formula (2) and p=q=1 in general formula (A);

in general formula (2), Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylalkylene group; and

in general formula (A), M and M′ each independently represent aheteroaromatic ring having 2 to 40 carbon atoms and nitrogen atom andforming a substituted or unsubstituted ring, and M and M′ may representa same ring or different rings, and L represents a substituted orunsubstituted aryl group or arylene group having 6 to 30 carbon atoms, asubstituted or unsubstituted cycloalkylene group having 5 to 30 carbonatoms or a substituted or unsubstituted heteroaromatic ring having 2 to30 carbon atoms.

In the above general formulae (1) and (2), it is preferable that Czrepresents a substituted or unsubstituted arylcarbazolyl group and, morepreferably, phenylcarbazolyl group. It is preferable that the arylportion of the arylcarbazolyl group is substituted with carbazolylgroup.

Specific examples of the compound represented by general formula (1) areshown in the following. However, the compound represented by generalformula (1) is not limited to these compounds.

Specific examples of the compound represented by general formula (2) areshown in the following. However, the compound represented by generalformula (2) is not limited to these compounds.

It is preferable that the energy gap of the triplet state of a compoundrepresented by general formula (1) or (2) is 2.5 to 3.3 eV and morepreferably 2.5 to 3.2 eV.

It is preferable that the energy gap of the singlet state of a compoundrepresented by general formula (1) or (2) is 2.8 to 3.8 eV and morepreferably 2.9 to 3.7 eV.

The organic EL device of the present invention comprises an anode, acathode and an organic thin film layer comprising at least one layerdisposed between the anode and the cathode, wherein at least one layerin the organic thin film layer comprises the material for organicelectroluminescence devices comprising the compound represented by theabove general formula (1) or (2).

It is preferable that the organic EL device of the present inventioncomprises the material for organic electroluminescence devicescomprising the compounds represented by the above general formula (1) or(2) in the light emitting layer, the electron transporting layer or thehole transporting layer.

The organic EL device of the present invention emits bluish light andthe purity of color of the emitted light is as excellent as (0.12, 0.10)to (0.17, 0.20). This property is exhibited since the material fororganic EL devices comprising the compound represented by generalformula (1) or (2) of the present invention has a great energy gap.

It is preferable that the organic EL device of the present inventionemits light by a multiplet excitation which is the excitation to thetriplet state or higher.

It is preferable that the material for organic electroluminescencedevices is a host material of the organic EL device. The host materialis a material into which holes and electrons can be injected and whichhas the function of transporting holes and electrons and emittingfluorescent light by recombination of holes and electrons.

The compounds represented by general formulae (1) and (2) in the presentinvention are useful also as the organic host material forphosphorescence devices since the energy gap of the singlet state is ashigh as 2.8 to 3.8 eV and the energy gap of the triplet state is as highas 2.5 to 3.3 eV.

The phosphorescence device is the organic device which comprises asubstance emitting light based on the transition from the energy levelof the triplet state to the energy level of the ground singlet statewith a stronger intensity than those emitted from other substances,i.e., a phosphorescent material such as organometallic complexescomprising at least one metal selected from Groups 7 to 11 of thePeriodic Table, and emits light under an electric field utilizing theso-called phosphorescence.

In the light emitting layer of the organic EL device, in general, thesinglet exciton and the triplet exciton are mixed in the formed excitedmolecules and it is said that the ratio of the amount of the singletexciton to the amount of the triplet exciton is 1:3 and the tripletexciton is formed in a greater amount. In conventional organic ELdevices using the phosphorescence, the exciton contributing to the lightemission is the singlet exciton and the triplet exciton does not emitlight. Therefore, the triplet exciton is ultimately consumed as heat andthe light is emitted by the singlet exciton which is formed in a smalleramount. Therefore, in these organic EL devices, the energy transferredto the triplet exciton in the energy generated by the recombination ofholes and electrons causes a great loss.

In contrast, it is considered that, by using the compound of the presentinvention for the phosphorescence device, the efficiency of lightemission three times as great as that of a device using a fluorescencecan be obtained since the triplet exciton can be used for emission oflight. It is also considered that, when the compound of the presentinvention is used for the light emitting layer of the phosphorescencedevice, an excited triplet state having an energy state higher than theexcited triplet state of a phosphorescent organometallic complexcomprising a metal selected from the Group 7 to 11 of the Periodic Tableis formed; the film having a more stable form is formed; the glasstransition temperature is higher (Tg: 80 to 160° C.); the holes and theelectrons are efficiently transported; the compound is electrochemicallyand chemically stable; and the formation of impurities which may work asa trap or causes the loss in the light emission is suppressed during thepreparation and the use.

The organic EL device of the present invention comprises, as describedabove, one or more organic thin film layers formed between the anode andthe cathode. When the device comprises a single layer, a light emittinglayer is formed between the anode and the cathode. The light emittinglayer comprises a light emitting material and, further, a hole injectingmaterial for transporting holes injected from the anode to the lightemitting material or an electron injecting material for transportingelectrons injected from the cathode to the light emitting material. Itis preferable that the light emitting material exhibits a very excellentphosphorescent quantum efficiency, has a great ability of transportingboth holes and electrons and forms a uniform thin layer. Examples of theorganic EL device of the multi-layer type include organic EL devicecomprising a laminate having a multi-layer construction such as (theanode/the hole injecting layer/the light emitting layer/the cathode),(the anode/the light emitting layer/the electron injecting layer/thecathode) and (the anode/the hole injecting layer/the light emittinglayer/the electron injecting layer).

For the light emitting layer, in addition to the compound represented bygeneral formula (1) or (2) of the present invention, conventional hostmaterials, light emitting materials, doping materials, hole injectingmaterials and electron injecting materials and combinations of thesematerials may be used, where necessary. By using a multi-layer.structure for the organic EL device, decreases in the luminance and thelife due to quenching can be prevented and the luminance of emittedlight and the efficiency of light emission can be improved with otherdoping materials. By using other doping materials contributing to thelight emission of the phosphorescence in combination, the luminance ofemitted light and the efficiency of light emission can be improved incomparison with conventional devices.

In the organic EL device of the present invention, the hole injectinglayer, the light emitting layer and the electron injecting layer mayeach have a multi-layer structure. When the hole injecting layer has amulti-layer structure, the layer into which holes are injected from theelectrode is called the hole injecting layer and the layer whichreceives holes from the hole injecting layer and transports holes to thelight emitting layer is called the hole transporting layer. Similarly,when the electron injecting layer has a multi-layer structure, the layerinto which electron are injected from the electrode is called theelectron injecting layer and the layer which receives electrons from theelectron injecting layer and transports electrons to the light emittinglayer is called the electron transporting layer. The layers are selectedin accordance with the energy levels of the material, heat resistanceand adhesion with the organic thin film layers or the metal electrodes.

In the organic EL device of the present invention, the electrontransporting layer and/or the hole transporting layer may comprise thematerial for organic EL devices of the present invention which comprisesany of the compounds represented by general formulae (1) and (2). Thehole injecting layer, the electron injecting layer and the hole barrierlayer may comprise the material for organic EL devices of the presentinvention. A phosphorescent light emitting compound and the material fororganic EL materials of the present invention may be used as a mixture.

Examples of the light emitting material and the host material which canbe used for the organic thin film layer in combination with the compoundrepresented by general formula (1) or (2) include anthracene,naphthalene, phenanthrene, pyrene, tetracene, coronen, chrysene,fluoresceine, perylene, phthaloperylene, naphthaloperylene, perynone,phthaloperynone, naphthaloperynone, diphenylbutadiene,tetraphenyl-butadiene, coumarine, oxadiazole, aldazine,bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, metal complexesof quinoline, metal complexes of aminoquinoline, metal complexes ofbenzoquinoline, imines, diphenylethylene, vinylanthracene,diaminoanthracene, diaminocarbazole, pyrane, thiopyrane, polymethine,melocyanine, oxinoid compounds chelated with imidazole, quinacridone,rubrene, stilbene-based derivatives and phosphorescent pigments.However, the light emitting material and the host material are notlimited to the compounds described above.

As the light emitting material, phosphorescent organometallic complexesare preferable since the external quantum efficiency of the device canbe improved. Examples of the metal in the phosphorescent organometalliccomplex include ruthenium, rhodium, palladium, silver, rhenium, osmium,iridium, platinum and gold. It is preferable that the organometalliccomplex is an organometallic compound represented-by the followinggeneral formula (3):

In the above general formula, A¹ represents a substituted orunsubstituted aromatic hydrocarbon cyclic group or aromatic heterocyclicgroup which is preferably phenyl group, biphenyl group, naphthyl group,anthryl group, thienyl group, pyridyl group, quinolyl group orisoquinolyl group. Examples of the substituent include halogen atomssuch as fluorine atom; alkyl groups having 1 to 30 carbon atoms such asmethyl group and ethyl group; alkenyl groups such as vinyl group;alkoxycarbonyl groups having 1 to 30 carbon atoms such asmethoxycarbonyl group and ethoxycarbonyl group; alkoxyl groups having 1to 30 carbon atoms such as methoxy group and ethoxyl group; aryloxygroups such as phenoxyl group and benzyloxyl group; dialkylamino groupssuch as dimethylamino group and diethylamino group; acyl groups such asacetyl group; haloalkyl groups such as trifluoromethyl group; and cyanogroup.

A² represents a substituted or unsubstituted aromatic heterocyclic grouphaving nitrogen atom as the atom forming the heterocyclic ring, which ispreferably pyridyl group, pirimidyl group, pyrazine group, triazinegroup, benzothiazole group, benzoxazole group, benzimidazole group,quinolyl group, isoquinolyl group, quinoxaline group or phenanthridinegroup. Examples of the substituent include the substituents described asthe examples of the substituent for the group represented by A¹.

The ring having the group represented by A¹ and the ring having thegroup represented by A² may form one condensed ring. Examples of thecondensed ring include 7,8-benzoquinoline group.

Q represents a metal selected from metals of Groups 7 to 11 of thePeriodic Table, which is preferably ruthenium, rhodium, palladium,silver, rhenium, osmium, iridium, platinum or gold.

L represents a bidentate ligand, which is preferably selected fromligands of the β-diketone type such as acetylacetonates and pyromelliticacid.

m and n each represent an integer. When Q represents a divalent metal,n=2 and m=0. When Q represents a trivalent metal, n=3 and m=0 or n=2 andm=1.

Specific examples of the organometallic complex represented by the abovegeneral formula (3) are shown in the following. However, theorganometallic complex is not limited to these compounds.

As the hole injecting material, compounds which have the ability totransport holes, exhibits the excellent effect of receiving holesinjected from the anode and the excellent effect of injecting holes tothe light emitting layer or the light emitting material, preventstransfer of excitons formed in the light emitting layer to the electroninjecting layer or the electron injecting material and has the excellentability of forming a thin film, are preferable. Examples of the holeinjecting compound include phthalocyanine derivatives, naphthalocyaninederivatives, porphyrin derivatives, oxazoles, oxadiazoles, triazoles,imidazoles, imidazolones, imidazolethiones, pyrazolines, pyrazolones,tetrahydroimidazoles, hydrazones, acylhydrazones, polyarylalkanes,stilbene, butadiene, triphenylamine of the benzidine type,triphenylamine of the styrylamine type, triphenylamine of the diaminetype, derivatives of the above compounds and macromolecular materialssuch as polyvinyl-carbazoles, polysilanes and electrically conductivemacromolecules. However, the hole injecting material is not limited tothese materials.

Among these hole injecting materials, the more effective hole injectingmaterials are aromatic tertiary amine derivatives and phthalocyaninederivatives. Examples of the aromatic tertiary amine derivative includetriphenylamine, tritolylamine, tolyldiphenylamine,N,N′-diphenyl-N,N′-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N,N′,N′-(4-methylphenyl)-1,1′-phenyl-4,4′-diamine,N,N,N′,N′-(4-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N′-diphenyl-N,N′-dinaphthyl-1,1′-biphenyl-4,4′-diamine,N,N′-(methylphenyl)-N,N′-(4-n-butylphenyl)-phenanthrene-9,10-diamine,N,N-bis(4-di-4-tolylaminophenyl)-4-phenyl-cyclohexane and oligomers andpolymers having the skeleton structure of these aromatic tertiaryamines. However, the aromatic tertiary amine is not limited to thesecompounds. Examples of the phthalocyanine (Pc) derivative includephthalocyanine derivatives and naphthalocyanine derivatives such asH₂Pc, CuPc, CoPc, NiPc, ZnPc, PdPc, FePc, MnPc, ClAlPC, ClGaPc, ClInPc,ClSnPc, Cl₂SiPc, (HO)AlPc, (HO)GaPc, VOPc, TiOPc, MoOPc and GaPc—O—GaPc.However the phthalocyanine derivative is not limited to these compounds.

As the electron injecting material, compounds which have the ability totransport electrons, exhibits the excellent effect of receivingelectrons injected from the anode and the excellent effect of injectingelectrons to the light emitting layer or the light emitting material,prevents transfer of excitons formed in the light emitting layer to thehole injecting layer and has the excellent ability of forming a thinfilm, are preferable. Examples of the electron injecting compoundinclude fluorenone, anthraquinodimethane, diphenoquinone, thiopyranedioxide, oxazoles, oxadiazoles, triazoles, imidazoles,perylenetetracarboxylic acid, quinoxaline, fluorenylidenemethane,anthraquinodimethane, anthrone and derivatives of these compounds.However, the electron injecting material is not limited to thesecompounds.

Among these electron injecting materials, the more effective electroninjecting materials are metal complex compounds and five-memberedderivatives having nitrogen. Examples of the metal complex compoundinclude 8-hydroxyquinolinatolithium, bis(8-hydroxyquinolinato)zinc,bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese,tris(8-hydroxyquinolinato)aluminum,tris(2-methyl-8-hydroxyquinolinato)aluminum,tris(8-hydroxyquinolinato)gallium,bis(10-hydroxybenzo[h]quinolinato)beryllium,bis(10-hydroxybenzo[h]quinolinato)zinc,bis(2-methyl-8-quinolinato)chlorogallium,bis(2-methyl-8-quinolinato)(o-cresolato)gallium,bis(2-methyl-8-quinolinato)(1-naphtholato)aluminum andbis(2-methyl-8-quinolinato)(2-naphtholato)gallium. However the electroninjecting material is not limited to these compounds.

As the five-membered derivative having nitrogen, oxazoles, thiazoles,oxadiazoles, thiadiazoles, triazoles and derivatives of these compoundsare preferable. Examples of the five-membered derivative having nitrogeninclude bis(1-phenyl)-1,3,4-oxazole, dimethylPOPOP,2,5-bis(1-phenyl)-1,3,4-thiazole, 2,5-bis(1-phenyl)-1,3,4-oxadiazole,2-(4′-tert-butylphenyl)-5-(4″-biphenyl)-1,3,5-oxadiazole,2,5-bis(1-naphthyl)-1,3,4-oxadiazole,1,4-bis[2-(5-phenyloxadiazolyl)]benzene,1,4-bis[2-(5-phenyloxadiazolyl)-4-tert-butylbenzene],2-(4′-tert-butylphenyl)-5-(4″-biphenyl)-1,3,4-thiadiazole,2,5-bis(1-naphthyl)-1,3,4-thiadiazole,1,4-bis[2-(5-phenylthiadiazolyl)]benzene,2-(4′-tert-butylphenyl)-5-(4″-biphenyl)-1,3,4-triazole,2,5-bis(1-naphthyl)-1,3,4-triazole and 1,4-bis[2-(5-phenyltriazolyl)]benzene. However, the five-membered derivativehaving nitrogen is not limited to these compounds.

The property of charge injection can be improved by adding anelectron-accepting compound to the hole injecting material and anelectron-donating compound to the electron injecting material.

As the electrically conductive material used for the anode of theorganic EL device of the present invention, a material having a workfunction greater than 4 eV is suitable and carbon, aluminum, vanadium,iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium,alloys of these metals, metal oxides such as tin oxides and indium oxideused for ITO substrates and NESA substrates and organic electricallyconductive resins such as polythiophene and polypyrrol are used. As theelectrically conductive material used for the cathode, a material havinga work function smaller than 4 eV is suitable and magnesium, calcium,tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminumand alloys of these metals are used. However, the electricallyconductive material used for the cathode is not limited to thesematerials. Typical examples of the alloy include magnesium/silver,magnesium/indium and lithium/aluminum. However, the alloy is not limitedto these alloys. The composition of the alloy is controlled by thetemperature of the source of vaporization, the atmosphere and the degreeof vacuum and a suitable composition is selected. The anode and thecathode may be formed with a structure having two or more layers, wherenecessary.

The organic EL device of the present invention may comprise an inorganiccompound layer between at least one of the electrodes and the aboveorganic thin film layer. Examples of the inorganic compound used for theinorganic compound layer include various types of oxides, nitrides andoxide nitrides such as alkali metal oxides, alkaline earth metal oxides,rare earth oxides, alkali metal halides, alkaline earth metal halides,rare earth halides, SiO_(x), AlO_(x), SiN_(x), SiON, AlON, GeO_(x),LiO_(x), LiON, TiO_(x), TiON, TaO_(x), TaON, TaN_(x) and C. Inparticular, as the component contacting the anode, SiO_(x), AlO_(x),SiN_(x), SiON, AlON, GeO_(x) and C are preferable since a stableinterface layer of injection is formed. As the component contacting thecathode, LiF, MgF₂, CaF₂ and NaF are preferable.

In the organic EL device of the present invention, it is preferable thatat least one face is sufficiently transparent in the region of thewavelength of the light emitted by the device so that the light emissionis achieved efficiently. It is preferable that the substrate is alsotransparent.

For the transparent electrode, the conditions in the vapor deposition orthe sputtering are set so that the prescribed transparency is surelyobtained using the above electrically conductive material. It ispreferable that the electrode of the light emitting face has atransmittance of light of 10% or greater. The substrate is notparticularly limited as long as the substrate has the mechanical andthermal strength and is transparent. Examples of the substrate includeglass substrates and transparent films of resins. Examples of thetransparent film of a resin include films of polyethylene,ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers,polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinylalcohol, polyvinyl butyral, nylon, polyether ether ketones,polysulfones, polyether sulfones, tetrafluoroethylene-perfluoroalkylvinyl ether copolymers, polyvinyl fluoride,tetrafluoro-ethylene-ethylene copolymers,tetrafluoroethylene-hexafluoropropylene copolymers,polychlorotrifluoroethylene, polyvinylidene fluoride, polyesters,polycarbonates, polyurethanes, polyether imides, polyimides andpolypropylene.

In the organic EL device of the present invention, it is possible that aprotective layer is formed on the surface of the device or the entiredevice is covered with a silicone oil or a resin so that stability tothe temperature, the humidity and the atmosphere is improved.

For the formation of each layer of the organic EL device of the presentinvention, any of the dry processes of film formation such as the vacuumvapor deposition, the sputtering, the plasma plating and the ion platingand the wet processes of film formation such as the spin coating, thedipping and the flow coating, can be applied. The thickness of each filmis not particularly limited. However, it is necessary that the thicknessof the film be set at a suitable value. When the thickness isexcessively great, application of a greater voltage is necessary toobtain the same output of the light and the efficiency of light emissiondecreases. When the thickness is excessively small, pin holes are formedand sufficient light emission cannot be obtained even when an electricfield is applied. In general, a thickness in the range of 5 nm to 10 μmis suitable and a thickness in the range of 10 nm to 0.2 μm ispreferable.

When the wet process of film formation is used, the material formingeach layer is dissolved or suspended in a suitable solvent such asethanol, chloroform, tetrahydrofuran and dioxane and a thin film isformed from the obtained solution or suspension. Any of the abovesolvents can be used. For any of the layers, suitable resins, andadditives may be used to improve the property for film formation and toprevent formation of pin holes in the film. Examples of the resin whichcan be used include insulating resins such as polystyrene,polycarbonates, polyarylates, polyesters, polyamides, polyurethanes,polysulfones, polymethyl methacrylate, polymethyl acrylate, celluloseand copolymers of these resins; photoconductive resins such aspoly-N-vinylcarbazole and polysilanes; and electrically conductiveresins such as polythiophene and polypyrrol. Examples of the additiveinclude antioxidants, ultraviolet light absorbents and plasticizers.

As described above, by using the compound represented by general formula(1) or (2) for the organic thin film layer of the organic EL device ofthe present invention, the organic EL device emitting blue light with ahigh purity of color can be obtained. This organic EL device can beadvantageously used for a photosensitive member for electronicphotograph, a planar light emitting member such as a flat panel displayof wall televisions, a back light of copiers, printers and liquidcrystal displays, a light source for instruments, a display panel, amarking light and an accessory.

The present invention will be described more specifically with referenceto examples in the following. However, the present invention is notlimited to the examples.

The triplet energy gap and the singlet energy gap of a compound weremeasured in accordance with the following methods.

(1) Measurement of the Triplet Energy Gap

The lowest excited triplet energy level T1 was measured. Thephosphorescence spectrum of a sample was measured (10 μmoles/liter; anEPA (diethyl ether:isopentane:ethanol=5:5:2 by volume) solution; 77K; aquartz cell; FLUOROLOG II manufactured by SPEX Company). A tangent wasdrawn to the increasing line at the short wavelength side of thephosphorescence spectrum and the wavelength at the intersection of thetangent and the abscissa (the end of light emission) was obtained. Theobtained wavelength was converted into the energy.

(2) Measurement of the Singlet Energy Gap

The excited singlet energy gap was measured. Using a toluene solution(10⁻⁵ moles/liter) of a sample, the absorption spectrum was obtained bya spectrometer for absorption of ultraviolet and visible lightmanufactured by HITACHI Co. Ltd. A tangent was drawn to the increasingline at the long wavelength side of the spectrum and the wavelength atthe intersection of the tangent and the abscissa (the end of absorption)was obtained. The obtained wavelength was converted into the energy.

SYNTHESIS EXAMPLE 1 Synthesis of Compound (A5)

The route of synthesis of Compound (A5) is shown in the following.

(1) Synthesis of Intermediate Compound (A)

2,4′-Dibromoacetophenone in an amount of 15 g (54 mmoles) was dissolvedinto 100 ml of ethanol. To the obtained solution, 7.0 g of sodiumhydrogencarbonate and 5.2 g (55 mmoles) of 2-aminopyridine were addedand the resultant mixture was heated for 9 hours under the refluxingcondition. After the reaction was completed, the mixture was cooled atthe room temperature. The formed crystals were separated by filtrationand washed with water and ethanol and 12.5 g (the yield: 85%) ofIntermediate Compound (A) was obtained.

(2) Synthesis of Compound (A5)

Into a reactor, 6.1 g (19 mmoles) of 3,6-diphenylcarbazole, 6.3 g (23mmoles) of Intermediate Compound (A), 0.2 g of copper powder, 1.7 g of18-crown-6 and 2.9 g (21 mmoles) of potassium carbonate were placed and30 ml of o-dichlorobenzene was added as the solvent. The resultantmixture was heated at 200° C. in a silicone oil bath under a nitrogenstream and the reaction was allowed to proceed for 48 hours. After thereaction was completed, the reaction mixture was filtered under suctionbefore being cooled and the obtained filtrate was concentrated using anevaporator. To the obtained oily product, 30 ml of methanol was added.The formed solid substance was separated by filtration under a reducedpressure and a gray solid substance was obtained. The obtained solidsubstance was recrystallized from benzene and 3.0 g (the yield: 31%) ofwhite crystals were obtained. It was confirmed by 90 MHz ¹H-NMR andFD-MS (the field desorption mass analysis) that the obtained crystalswere the target substance (A5). The result of the measurement by FD-MSis shown in the following:

-   -   FD-MS calcd. for C₃₇H₂₅N₃=511; found: m/z=511 (M⁺, 100)

The values of the energy gaps were obtained in accordance with themethods described above and the results are shown in Table 3.

SYNTHESIS EXAMPLE 2 Synthesis of Compound (A3)

The route of synthesis of Compound (A3) is shown in the following.

(1) Synthesis of Intermediate Compound (B)

4-Bromobenzaldehyde in an amount of 15 g (81 mmoles) was dissolved into300 ml of ethanol. To the obtained solution, 10 g (83 mmoles) of2-acetylpyridine and 15 g (81 mmoles) of a 28% methanol solution ofsodium methoxide were added and the resultant mixture was stirred at theroom temperature for 7 hours. After the reaction was completed, theformed crystals were separated by filtration and washed with ethanol and9.5 g (the yield: 41%) of Intermediate Compound (B) was obtained.

(2) Synthesis of Intermediate Compound (C)

Intermediate Compound (B) in an amount of 9.5 g (33 mmoles) wasdissolved into 80 ml of ethanol. To the obtained solution, 5.2 g (34mmoles) of benzamidine hydrochloride and 2.6 g (65 mmoles) of sodiumhydroxide were added and the resultant mixture was heated for 15 hoursunder the refluxing condition. After the reaction was completed, themixture was cooled at the room temperature. The formed crystals wereseparated by filtration and washed with water and ethanol and 3.46 g(the yield: 27%) of Intermediate Compound (C) was obtained.

(3) Synthesis of Compound (A3)

Into a reactor, 6.1 g (19 mmoles) of 3,6-diphenylcarbazole, 8.9 g (23mmoles) of Intermediate Compound (C), 0.2 g of copper powder, 1.7 g of18-crown-6 and 2.9 g (21 mmoles) of potassium carbonate were placed and30 ml of o-dichlorobenzene was added as the solvent. The resultantmixture was heated at 200° C. in a silicone oil bath under a nitrogenstream and the reaction was allowed to proceed for 48 hours. After thereaction was completed, the reaction mixture was filtered under suctionbefore being cooled and the obtained filtrate was concentrated using anevaporator. To the obtained oily product, 30 ml of methanol was added.The formed solid substance was separated by filtration under a reducedpressure and a gray solid substance was obtained. The obtained solidsubstance was recrystallized from benzene and 3.9 g (the yield: 33%) ofwhite crystals were obtained. It was confirmed by 90 MHz ¹H-NMR andFD-MS that the obtained crystals were the target substance (A3). Theresult of the measurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₄₅H₃₀N₄=626; found: m/z=626 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 3 Synthesis of Compound (A26)

The route of synthesis of Compound (A26) is shown in the following.

(1) Synthesis of Intermediate Compound (D)

Into a reactor, 33 g (0.20 moles) of carbazole, 68 g (0.24 moles) ofp-bromoiodobenzene, 2.0 g of copper powder, 18 g of 18-crown-6 and 30 g(0.22 moles) of potassium carbonate were placed and 300 ml ofo-dichlorobenzene was added as the solvent. The resultant mixture washeated at 200° C. in a silicone oil bath under a nitrogen stream and thereaction was allowed to proceed for 24 hours. After the reaction wascompleted, the reaction mixture was filtered under suction using aBuchner funnel before being cooled and the obtained filtrate wasconcentrated using an evaporator. To the obtained oily product, 30 ml ofmethanol was added. The formed solid substance was separated byfiltration under a reduced pressure and a gray solid substance wasobtained. The obtained solid substance was recrystallized from benzeneand 31 g (the yield: 49%) of white crystals were obtained.

(2) Synthesis of Compound (A26)

Into a reactor, 5.4 g (20 mmoles) of 2-biphenylindole, 7.7 g (24 mmoles)of Intermediate Compound (D), 0.2 g of copper powder, 1.8 g of18-crown-6 and 3.0 g (22 mmoles) of potassium carbonate were placed and30 ml of o-dichlorobenzene was added as the solvent. The resultantmixture was heated at 200° C. in a silicone oil bath under a nitrogenstream and the reaction was allowed to proceed for 48 hours. After thereaction was completed, the reaction mixture was filtered under suctionbefore being cooled and the obtained filtrate was concentrated using anevaporator. To the obtained oily product, 30 ml of methanol was added.The formed solid substance was separated by filtration under a reducedpressure and a gray solid substance was obtained. The obtained solidsubstance was recrystallized from benzene and 1.7 g (the yield: 17%) ofwhite crystals were obtained. It was confirmed by 90 MHz ¹H-NMR andFD-MS that the obtained crystals were the target substance (A26). Theresult of the measurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₃₈H₂₆N₂=510; found: m/z=510 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 4 Synthesis of Compound (A27)

The route of synthesis of Compound (A27) is shown in the following.

In accordance with the same procedures as those conducted in SynthesisExample 3 (2) except that 2-biphenyl-3-phenylindole was used in place of2-biphenylindole, 2.2 g (the yield: 19%) of white crystals wereobtained. It was confirmed by 90 MHz ¹H-NMR and FD-MS that the obtainedcrystals were the target substance (A27). The result of the measurementby FD-MS is shown in the following:

-   -   FD-MS calcd. for C₄₄H₃₀N₂=586; found: m/z=586 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 5 Synthesis of Compound (A11)

The route of synthesis of Compound (A11) is shown in the following.

(1) Synthesis of Intermediate Compound (E)

3,6-Biphenyl-9-p-bromophenylcarbazole in an amount of 7.6 g (16 mmoles)was dissolved into 70 ml of ether. To the obtained solution, 12 ml of ahexane solution (1.6 M) of n-butyllithium was added at −60° C. After theresultant solution was stirred at a temperature between −60° C. and 0°C. for 2 hours, the solution was cooled at −60° C. again and a solutionobtained by diluting 8.8 g of triisopropyl borate with 10 ml of etherwas added dropwise. After the resultant mixture was stirred at atemperature between −60° C. and 0° C. for 2 hours, the reaction wasquenched by adding a 5% aqueous solution of hydrochloric acid. Theformed crystals were separated by filtration and washed with water andmethanol and 4.0 g (the yield: 58%) of Intermediate Compound (E) wasobtained.

(2) Synthesis of Compound (A11)

2-(4′-Bromophenyl)imidazo[1,2-a]pyridine in an amount of 2.0 g (7.3mmoles), 3.5 g (8.0 mmoles) of Intermediate Compound (E), 0.2 g ofcopper powder and 0.17 g of tetrakis(triphenylphosphine)palladium weredissolved into 30 ml of 1,2-dimethoxyethane. To the resultant solution,12 ml of a 2.0 M aqueous solution of sodium carbonate was added and theobtained solution was heated for 8 hours under the refluxing condition.After the reaction was completed, the formed solid substance wasdissolved into dichloromethane, washed with water and dried with sodiumsulfate. After the solvent was removed by distillation, the obtainedproduct was washed with methanol and 2.0 g (the yield: 47%) of yellowishwhite solid substance was obtained. It was confirmed by 90 MHz ¹H-NMRand FD-MS that the obtained solid substance was the target substance(A11). The result of the measurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₄₃H₂₉N₃=587; found: m/z=587 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 6 Synthesis of Compound (A9)

The route of synthesis of Compound (A9) is shown in the following.

Intermediate Compound (C) obtained in Synthesis Example 2 in an amountof 2.0 g (5.2 mmoles), 1.7 g (5.8 mmoles) of4-(9′-carbazolyl)-phenylboric acid and 0.11 g oftetrakis(triphenylphosphine)palladium were dissolved into 20 ml of1,2-dimethoxyethane. To the resultant solution, 9 ml of a 2.0 M aqueoussolution of sodium carbonate was added and the obtained solution washeated for 8 hours under the refluxing condition. After the reaction wascompleted, the formed solid substance was dissolved intodichloromethane, washed with water and dried with sodium sulfate. Afterthe solvent was removed by distillation, the obtained product was washedwith methanol and 1.8 g (the yield: 62%) of yellowish white solidsubstance was obtained. It was confirmed by 90 MHz ¹H-NMR and FD-MS thatthe obtained solid substance was the target substance (A9). The resultof the measurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₃₉H₂₆N₄=550; found: m/z=550 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 7 Synthesis of Compound (A43)

The route of synthesis of Compound (A43) is shown in the following.

Under a stream of argon, 2.33 g (10 mmoles) of2,3-dicyano-5-(p-bromophenyl)-7-methyl-6H-1,4-diazepine, 2 g (12 mmoles)of carbazole, 0.14 g (1.5% by mole) oftris(dibenzylideneacetone)dipalladium, 0.06 g (3% by mole) oftri-t-butylphosphine, 2.0 g (22 mmoles) of sodium t-butoxide and 100 mlof dry toluene were placed into a 200 ml three-necked flask equippedwith a condenser and the resultant mixture was heated at 100° C. understirring for one night. After the reaction was completed, the formedcrystals were separated by filtration and washed with 100 ml of methanoland 1.2 g (3 mmoles) (the yield: 30%) of a light yellow powder wasobtained. It was confirmed by the measurements of NMR, IR and FD-MS thatthe obtained powder was the target substance (A43). The result of themeasurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₂₆H₁₇N₅=399; found: m/z=399 (M⁺, 100)

SYNTHESIS EXAMPLE 8 Synthesis of Compound (A45)

The route of synthesis of Compound (A45) is shown in the following.

Under a stream of argon, 4.5 g (10 mmole) of2,3-dicyano-5,7-bis(p-bromophenyl)-6H-1,4-diazepine, 4 g (24 mmoles) ofcarbazole, 0.28 g (1.5% by mole) oftris(dibenzylideneacetone)dipalladium, 0.12 g (3% by mole) oftri-t-butylphosphine, 4.2 g (442 mmoles) of sodium t-butoxide and 160 mlof dry toluene were placed into a 200 ml three-necked flask equippedwith a condenser and the resultant mixture was heated at 100° C. understirring for 18 hours. After the reaction was completed, the formedcrystals were separated by filtration and washed with 100 ml of methanoland 1.8 g (2.9 mmoles) (the yield: 29%) of a white powder was obtained.It was confirmed by the measurements of NMR, IR and FD-MS that theobtained powder was the target substance (A45). The result of themeasurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₄₃H₂₆N₆=626; found: m/z=626 (M⁺, 100)

SYNTHESIS EXAMPLE 9 Synthesis of Compound (B9)

The route of synthesis of Compound (B9) is shown in the following.

Under the atmosphere of argon, 11 g (32 mmole, 2.6 eq) of4-(2′-phenyl-4′-pyridylpirimidin-6′-yl)phenylboric acid, 5 g (12 mmoles)of 3,6-dibromo-9-phenylcarbazole and 0.55 g (0.48 mmoles, 2% Pd) oftetrakis(triphenylphosphine)palladium(0) were suspended in 100 ml of1,2-dimethoxyethane. To the resultant suspension, 10.2 g of a 2 Maqueous solution of sodium carbonate (96 mmoles, 3 eq/50 ml) was addedand the resultant mixture was heated for 10 hours under the refluxingcondition. After the organic layer was separated and concentrated, theproduct was purified in accordance with the column chromatography and8.5 g (the yield: 83%) of a white solid substance was obtained. It wasconfirmed by 90 MHz ¹H-NMR and FD-MS that the obtained solid substancewas the target substance (B9). The result of the measurement by FD-MS isshown in the following:

-   -   FD-MS calcd. for C₆₀H₃₉N₇=857; found: m/z=857 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 10 Synthesis of Compound (B11)

The route of synthesis of Compound (B11) is shown in the following.

Under the atmosphere of argon, 7.6 g (32 mmole, 2.6 eq) of4-(imidazopyridin-2′-yl)phenylboric acid, 5 g (12 mmoles) of3,6-dibromo-9-phenylcarbazole and 0.55 g (0.48 mmoles, 2% Pd) oftetrakis(triphenylphosphine)palladium(0) were suspended in 100 ml of1,2-dimethoxyethane. To the resultant suspension, 10.2 g of a 2 Maqueous solution of sodium carbonate (96 mmoles, 3 eq/50 ml) was addedand the resultant mixture was heated for 10 hours under the refluxingcondition. After the organic layer was separated and concentrated, theproduct was purified in accordance with the column chromatography and5.7 g (the yield: 76%) of a white solid substance was obtained. It wasconfirmed by 90 MHz ¹H-NMR and FD-MS that the obtained solid substancewas the target substance (B11). The result of the measurement by FD-MSis shown in the following:

-   -   FD-MS calcd. for C₄₄H₂₉N₅=627; found: m/z=627 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 11 Synthesis of Compound (A72)

The route of synthesis of Compound (A72) is shown in the following.

(1) Synthesis of Intermediate Compound (F)

In accordance with the same procedures as those conducted in SynthesisExample 2 (1) except that acetophenone was used in place of2-acetylpyridine, 29.4 g (the yield: 84%) of Intermediate Compound (F)was obtained.

(2) Synthesis of Intermediate Compound (G)

Intermediate Compound (F) in an amount of 9.0 g (31 mmoles), 8.7 g (31mmoles) of 1-phenylpyridinium bromide and 19.3 g (250 mmoles) ofammonium acetate were suspended into 27 ml of acetic acid and theresultant suspension was heated for 12 hours under the refluxingcondition. The reaction solution was then cooled at the roomtemperature. Toluene and water were added and the resultant mixture wasseparated into two layers. The organic layer was washed with a 10%aqueous solution of sodium hydroxide and a saturated aqueous solution ofsodium chloride, successively, and dried with anhydrous sodium sulfate.After the organic solvent was removed by distillation under a reducedpressure, 27 ml of ethanol was added. The formed crystals were separatedby filtration and washed with ethanol and 10.6 g (the yield: 88%) ofIntermediate Compound (G) was obtained.

(3) Synthesis of Compound (A72)

Intermediate Compound (G) in an amount of 3.5 g (9 mmoles), 1.7 g (10mmoles) of carbazole, 0.09 g (0.5 mmoles) of copper iodide and 4.0 g (19mmoles) of potassium phosphate were suspended into 18 ml of 1,4-dioxane.To the obtained suspension, 0.5 ml (4 mmoles) oftrans-1,2-cyclohexanediamine was added. Under the atmosphere of argon,the resultant mixture was heated for 18 hours under the refluxingcondition. The reaction solution was then cooled at the roomtemperature. Methylene chloride and water were added and the resultantmixture was separated into two layers. The organic layer was washed witha 5% aqueous solution of hydrochloric acid and water, successively, anddried with anhydrous sodium sulfate. After the organic solvent wasremoved by distillation, 15 ml of ethyl acetate was added. The formedcrystals were separated by filtration and washed with ethyl acetate and3.5 g (the yield: 83%) of yellowish white crystals were obtained. It wasconfirmed by 90 MHz ¹H-NMR and FD-MS that the obtained crystals were thetarget substance (A72). The result of the measurement by FD-MS is shownin the following:

-   -   FD-MS calcd. for C₃₅H₂₄N₂=472; found: m/z=472 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 12 Synthesis of Compound (A73)

The route of synthesis of Compound (A73) is shown in the following.

(1) Synthesis of Intermediate Compound (H)

In accordance with the same procedures as those conducted in SynthesisExample 2 (2) except that Intermediate Compound (F) obtained inSynthesis Example 11 was used in place of Intermediate Compound (B), 7.8g (the yield: 61%) of Intermediate Compound (H) was obtained.

(2) Synthesis of Compound (A73)

In accordance with the same procedures as those conducted in SynthesisExample 11 (3) except that Intermediate Compound (H) was used in placeof Intermediate Compound (G), 3.3 g (the yield: 76%) of yellowish whitecrystals were obtained. It was confirmed by 90 MHz ¹H-NMR and FD-MS thatthe obtained crystals were the target substance (A73). The result of themeasurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₃₄H₂₃N₃=473; found: m/z=473 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 13 Synthesis of Compound (A113)

The route of synthesis of Compound (A113) is shown in the following.

In accordance with the same procedures as those conducted in SynthesisExample 11 (3) except that Intermediate Compound (C) obtained inSynthesis Example 2 was used in place of Intermediate Compound (G), 1.5g (the yield: 50%) of yellowish white crystals were obtained. It wasconfirmed by 90 MHz ¹H-NMR and FD-MS that the obtained crystals were thetarget substance (A113). The result of the measurement by FD-MS is shownin the following:

-   -   FD-MS calcd. for C₃₃H₂₂N₄=474; found: m/z=474 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 14 Synthesis of Compound (A98)

The route of synthesis of Compound (A98) is shown in the following.

(1) Synthesis of Intermediate Compound (J)

In accordance with the same procedures as those conducted in SynthesisExample 2 (1) except that 3,5-dibromobenzaldehyde was used in place of4-bromobenzaldehyde and acetophenone was used in place of2-acetylpyridine, 19.2 g (the yield: 92%) of Intermediate Compound (J)was obtained.

(2) Synthesis of Intermediate Compound (K)

In accordance with the same procedures as those conducted in SynthesisExample 2 (2) except that Intermediate Compound (J) was used in place ofIntermediate Compound (B), 5.5 g (the yield: 45%) of IntermediateCompound (K) was obtained.

(3) Synthesis of Compound (A98)

Intermediate Compound (K) in an amount of 3.0 g (6 mmoles), 2.3 g (14mmoles) of carbazole, 0.12 g (0.6 mmoles) of copper iodide and 4.2 g (20mmoles) of potassium phosphate were suspended into 21 ml of 1,4-dioxane.To the obtained suspension, 0.8 ml (6 mmoles) oftrans-1,2-cyclohexanediamine was added. Under the atmosphere of argon,the resultant mixture was heated for 18 hours under the refluxingcondition. The reaction solution was then cooled at the roomtemperature. Methylene chloride and water were added and the resultantmixture was separated into two layers. The organic layer was washed withwater and dried with anhydrous sodium sulfate. After the organic solventwas removed by distillation under a reduced pressure, the residue ofdistillation was suspended into 21 ml of dioxane. To the obtainedsuspension, 0.12 g (0.6 mmoles) of copper iodide, 2.9 g (14 mmoles) ofpotassium phosphate and 0.8 ml (6 mmoles) oftrans-1,2-cyclohexanediamine were added. Under the atmosphere of argon,the resultant mixture was heated for 18 hours under the refluxingcondition. The reaction solution was then cooled at the roomtemperature. Methylene chloride and water were added and the resultantmixture was separated into two layers. The organic layer was washed withwater and dried with anhydrous sodium sulfate. After the organic solventwas removed by distillation under a reduced pressure, 30 ml of ethylacetate was added. The formed crystals were separated by filtration andwashed with ethyl acetate and 3.3 g (the yield: 80%) of yellowish whitecrystals were obtained. It was confirmed by 90 MHz ¹H-NMR and FD-MS thatthe obtained crystals were the target substance (A98). The result of themeasurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₄₆H₃₀N₄=638; found: m/z=638 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 15 Synthesis of Compound (A105)

The route of synthesis of Compound (A105) is shown in the following.

(1) Synthesis of Intermediate Compound (M)

In accordance with the same procedures as those conducted in SynthesisExample 11 (2) except that Intermediate Compound (J) obtained inSynthesis Example 14 (1) was used in place of Intermediate Compound (F),10.0 g (the yield: 88%) of Intermediate Compound (M) was obtained.

(2) Synthesis of Compound (A105)

In accordance with the same procedures as those conducted in SynthesisExample 14 (3) except that Intermediate Compound (M) was used in placeof Intermediate Compound (K), 2.9 g (the yield: 71%) of yellowish whitecrystals were obtained. It was confirmed by 90 MHz ¹H-NMR and FD-MS thatthe obtained crystals were the target substance (A105). The result ofthe measurement by FD-MS is shown in the following:

-   -   FD-MS calcd. for C₄₇H₃₁N₃=637; found: m/z=637 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

SYNTHESIS EXAMPLE 16 Synthesis of Compound (A108)

The route of synthesis of Compound (A108) is shown in the following.

(1) Synthesis of Intermediate Compound (N)

1,3,5-Tribromobenzene in an amount of 13.0 g (41 mmoles), 10.0 g (45mmoles) of 3,5-diphenylpyrazole, 0.8 g (4 mmoles) of copper iodide and11.9 g (86 mmoles) of potassium carbonate were suspended into 50 ml of1,4-dioxane. To the obtained suspension, 4.9 ml (41 mmoles) oftrans-1,2-cyclohexanediamine was added. Under the atmosphere of argon,the resultant mixture was heated for 18 hours under the refluxingcondition. The reaction solution was then cooled at the roomtemperature. Methylene chloride and water were added and the resultantmixture was separated into two layers. The organic layer was washed withwater and dried with anhydrous sodium sulfate. After the organic solventwas removed by distillation under a reduced pressure, the remainingproduct was purified in accordance with the silica gel columnchromatography and 2.0 g (the yield: 11%) of Intermediate Compound (N)was obtained.

(2) Synthesis of Compound (A108)

Intermediate Compound (N) in an amount of 2.0 g (4 mmoles), 1.4 g (8mmoles) of carbazole, 0.08 g (0.4 mmoles) of copper iodide and 2.9 g (14mmoles) of potassium phosphate were suspended into 15 ml of 1,4-dioxane.To the obtained suspension, 0.5 ml (4 mmoles) oftrans-1,2-cyclohexanediamine was added. Under the atmosphere of argon,the resultant mixture was heated for 18 hours under the refluxingcondition. The reaction solution was then cooled at the roomtemperature. Methylene chloride and water were added and the resultantmixture was separated into two layers. The organic layer was washed withwater and dried with anhydrous sodium sulfate. After the organic solventwas removed by distillation, the residue of distillation was suspendedinto 15 ml of 1,4-dioxane. To the obtained suspension, 0.08 g (0.4mmoles) of copper iodide, 2.9 g (14 mmoles) of potassium phosphate and0.5 ml (4 mmoles) of trans-1,2-cyclohexanediamine were added. Under theatmosphere of argon, the resultant mixture was heated for 14 hours underthe refluxing condition. The reaction solution was then cooled at theroom temperature. Methylene chloride and water were added and theresultant mixture was separated into two layers. The organic layer waswashed with water and dried with anhydrous sodium sulfate. After theorganic solvent was removed by distillation under a reduced pressure, 5ml of ethanol and 15 ml of ethyl acetate were added. The formed crystalswere separated by filtration and washed with a mixed solvent containingethyl acetate and ethanol in relative amounts by volume of 5:2 and 2.4 g(the yield: 87%) of yellowish white crystals were obtained. It wasconfirmed by 90 MHz ¹H-NMR and FD-MS that the obtained crystals were thetarget substance (A108). The result of the measurement by FD-MS is shownin the following:

-   -   FD-MS calcd. for C₄₅H₃₀N₄=626; found: m/z=626 (M⁺, 100)

The values of the energy gaps were obtained in accordance with the samemethods as those in Synthesis Example 1 and the results are shown inTable 3.

TABLE 3 Singlet Triplet energy gap energy gap Compound (eV) (eV)Synthesis Example 1 A5 3.2 2.7 Synthesis Example 2 A3 3.1 2.7 SynthesisExample 3 A26 3.1 2.6 Synthesis Example 4 A27 3.0 2.6 Synthesis Example5 A11 3.0 2.7 Synthesis Example 6 A9 3.1 2.5 Synthesis Example 9 B9 3.22.6 Synthesis Example 10 B11 3.2 2.7 Synthesis Example 11 A72 3.5 2.8Synthesis Example 12 A73 3.3 2.8 Synthesis Example 13 A113 3.2 2.7Synthesis Example 14 A98 3.5 2.9 Synthesis Example 15 A105 3.4 2.9Synthesis Example 16 A108 3.7 3.0

EXAMPLE 1

A glass substrate (manufactured by GEOMATEC Company) of 25 mm×75 mm×1.1mm thickness having an ITO transparent electrode was cleaned byapplication of ultrasonic wave in isopropyl alcohol for 5 minutes andthen by exposure to ozone generated by ultraviolet light for 30 minutes.The glass substrate having the transparent electrode lines which hadbeen cleaned was attached to a substrate holder of a vacuum vapordeposition apparatus. On the surface of the cleaned substrate at theside having the transparent electrode, a film ofN,N′-bis(N,N′-diphenyl-4-aminophenyl)-N,N′-diphenyl-4,4′-diamino-1,1′-biphenyl(a film of TPD232) having a thickness of 60 nm was formed in a mannersuch that the formed film covered the transparent electrode. The formedfilm of TPD232 worked as the hole injecting layer. On the formed film ofTPD232, a film of 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (a filmof NPD) having a thickness of 20 nm was formed by vapor deposition. Theformed film of NPD worked as the hole transporting layer. On the formedfilm of NPD, a film of the above Compound (A5) having a thickness of 40nm was formed by vapor deposition. At the same time, Compound (D1) shownin the following was vapor deposited in an amount such that the ratio ofthe amounts by weight of Compound (A5) to Compound (Di) was 40:3.Compound (D1) is a light emitting compound having a singlet energy aslow as 2.79 eV so that blue light is emitted. The formed mixed film ofCompound (A5) and Compound (D1) worked as the light emitting layer. Onthe film formed above, a film of BAlq shown in the following (Me meansmethyl group) having a thickness of 20 nm was formed. The film of BAlqworked as the electron injecting layer. Thereafter, Li (the source oflithium: manufactured by SAES GETTERS Company) as the reducing dopantand Alq were binary vapor deposited and an Alq:Li film having athickness of 10 nm was formed as the second electron injecting layer(the cathode). On the formed Alq:Li film, metallic aluminum was vapordeposited to form a metal cathode and an organic EL device was prepared.

When a direct current voltage of 5.0 V was applied to the organic ELdevice prepared above, blue light was emitted at a luminance of 150cd/m² and an efficiency of the light emission of 6.3 cd/A. The chromaticcoordinates were (0.14, 0.16) and the purity of color was excellent.

EXAMPLES 2 TO 8

In accordance with the same procedures as those conducted in Example 1except that compounds shown in Table 4 were used in place of Compound(A5), organic EL devices were prepared and the voltage of the directcurrent, the luminance of the emitted light, the efficiency of the lightemission, the color of the emitted light and the purity of color weremeasured. The results are shown in Table 4.

COMPARATIVE EXAMPLE 1

In accordance with the same procedures as those conducted in Example 1except that a conventional compound BCz shown in the following was usedin place of Compound (A5), an organic EL device was prepared and thevoltage of the direct current, the luminance of the emitted light, theefficiency of the light emission, the color of the emitted light and thepurity of color were measured. The results are shown in Table 4.

COMPARATIVE EXAMPLE 2

In accordance with the same procedures as those conducted in Example 1except that Compound (C2) shown in the following which is described inJapanese Patent Application Laid-Open No. 2001-288462 was used in placeof Compound (A5), an organic EL device was prepared and the voltage ofthe direct current, the luminance of the emitted light, the efficiencyof the light emission, the color of the emitted light and the purity ofcolor were measured. The results are shown in Table 4.

TABLE 4 (C2)

Organic Luminance Efficiency host material of emitted of light Color ofof light Voltage light emission emitted Chromatic emitting layer (V)(cd/m²) (cd/A) light coordinates Example 1 A5 5.0 150 6.3 blue (0.14,0.16) Example 2 A3 5.8 160 5.8 blue (0.15, 0.17) Example 3 A26 6.0 1325.2 blue (0.14, 0.16) Example 4 A27 6.0 154 5.9 blue (0.14, 0.16)Example 5 A11 5.2 180 6.3 blue (0.15, 0.17) Example 6 A9 6.2 145 5.1blue (0.15, 0.16) Example 7 B9 5.7 151 5.7 blue (0.15, 0.17) Example 8B11 5.0 181 6.9 blue (0.15. 0.17) Comparative BCz 8.5 70 2.4 blue (0.14,0.16) Example 1 Comparative C2 6.5 65 2.6 blue (0.14, 0.16) Example 2

As shown in Table, 4, in comparison with the organic EL devices usingconventional compounds BCz and (C2) in Comparative Examples 1 and 2,respectively, the organic EL devices using the compounds of the presentinvention could be driven at lower voltages and emitted blue light inhigher efficiencies. Since the energy gap of the compounds of thepresent invention is great, light emitting molecules having a greatenergy gap could be mixed into the light emitting layer and used for thelight emission.

EXAMPLE 9

A glass substrate (manufactured by GEOMATEC Company) of 25 mm×75 mm×0.7mm thickness having an ITO transparent electrode was cleaned byapplication of ultrasonic wave in isopropyl alcohol for 5 minutes andthen by exposure to ozone generated by ultraviolet light for 30 minutes.The glass substrate having the transparent electrode lines which hadbeen cleaned was attached to a substrate holder of a vacuum vapordeposition apparatus. On the surface of the cleaned substrate at theside having the transparent electrode, a film of copper phthalocyanineshown in the following (a film of CuPc) having a thickness of 10 nm wasformed in a manner such that the formed film covered the transparentelectrode. The formed film of CuPc worked as the hole injecting layer.On the formed film of CuPc, a film of1,1′-bis[4-N,N-di(p-tolyl)aminophenyl]cyclohexane (a film of TPAC)having a thickness of 30 nm was formed. The formed film of TPAC workedas the hole transporting layer. On the formed film of TPAC, a film ofthe above Compound (A72) having a thickness of 30 nm was formed by vapordeposition and the light emitting layer was formed. At the same time, Irbis[(4,6-difluorophenyl)pyridinato-N,C²′] picolinate (FIrpic shown inthe following) as the phosphorescent Ir metal complex was added. Theconcentration of FIrpic in the light emitting layer was set at 7% byweight. This layer worked as the light emitting layer. On the filmformed above, a film of Alq having a thickness of 30 nm was formed. Thefilm of Alq worked as the electron injecting layer. Thereafter, LiF asthe alkali metal halide was vapor deposited in an amount such that theformed film had a thickness of 0.2 nm and, then, aluminum was vapordeposited in an amount such that the formed film had a thickness of 150nm. The formed film of Alq:Li film worked as the cathode. Thus, anorganic EL device was prepared.

When the obtained device was tested by passing the electric current,bluish green light having a luminance of 89 cd/m² was emitted at avoltage of 6.6 V and a current density of 0.59 mA/cm². The chromaticcoordinates were (0.18, 0.39) and the efficiency of the light emissionwas 14.98 cd/A.

EXAMPLES 10 TO 12

In accordance with the same procedures as those conducted in Example 9except that compounds shown in Table 5 were used in place of Compound(A72), organic EL devices were prepared and the voltage of the directcurrent, the current density, the luminance of the emitted light, theefficiency of the light emission, the color of the emitted light and thepurity of color were measured. The results are shown in Table 5.

COMPARATIVE EXAMPLE 3

In accordance with the same procedures as those conducted in Example 9except that the conventional compound BCz was used in place of Compound(A72), an organic EL device was prepared and the voltage of the directcurrent, the current density, the luminance of the emitted light, theefficiency of the light emission, the color of the emitted light and thepurity of color were measured. The results are shown in Table 5.

COMPARATIVE EXAMPLE 4

In accordance with the same procedures as those conducted in ComparativeExample 3 except that 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(α-NPD shown in the following) was used for the hole transporting layerin place of the compound TPAC and BAlq shown above was used for theelectron transporting layer in place of the compound Alq, an organic ELdevice was prepared and the voltage of the direct current, the currentdensity, the luminance of the emitted light, the efficiency of the lightemission, the color of the emitted light and the purity of color weremeasured. The results are shown in Table 5.

TABLE 5

Organic Luminance Efficiency host of of material of Current emittedlight Color of Chromatic light emitt- Voltage density light emissionemitted coordi- ing layer (V) (mA/cm²) (cd/m²) (cd/A) light natesExample 9 A72 6.6 0.59 89 14.98 bluish (0.18, 0.39) green Example 10 A986.4 0.54 86 15.89 bluish (0.18, 0.40) green Example 11 A105 6.9 0.84 9911.76 bluish (0.17, 0.40) green Example 12 A73 6.0 1.00 99 9.91 bluish(0.16, 0.39) green Comparative BCz 7.8 1.70 98 5.80 bluish (0.16, 0.37)Example 3 green Comparative BCz 7.6 1.09 99 9.15 bluish (0.17, 0.37)Example 4 green

As shown in Table 5, in comparison with the organic EL devices using theconventional compound BCz in Comparative Examples 3 and 4, the organicEL devices using the compounds of the present invention could be drivenat a lower voltage and emit blue light at a higher efficiency. Since theenergy gap of the compounds of the present invention is great, lightemitting molecules having a great energy gap could be mixed into thelight emitting layer and used for the light emission.

INDUSTRIAL APPLICABILITY

As described above in detail, by utilizing the material for organicelectroluminescence devices comprising the compound represented bygeneral formula (1) or (2) of the present invention, the organicelectroluminescence device emitting blue light with a high efficiency oflight emission and an excellent purity of color can be obtained.Therefore, the organic electroluminescence device of the presentinvention is very useful as the light source for various electronicinstruments.

What is claimed is:
 1. A material for organic electroluminescencedevices which comprises a compound represented by following generalformula (1):(Cz-)_(n)A   (1) wherein Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylalkylene group, wherein thearylcarbazolyl group is bonded to A via the aryl portion of thearylcarbazolyl group or via the carbazolyl portion of the arylcarbazolylgroup and A represents a group represented by following general formula(A):(M)_(p)-(L)_(q)-(M′)_(r)   (A) wherein M represents an unsubstitutedpyrimidine or a pyrimidine substituted with at least one group selectedfrom the group consisting of a halogen atom, a carbazole group, ahydroxyl group, a substituted amino group, an unsubstituted amino group,a nitro group, a cyano group, a silyl group, a trifluoromethyl group, acarbonyl group, a carboxyl group, a substituted alkyl group, anunsubstituted alkyl group, a substituted alkenyl group, an unsubstitutedalkenyl group, a substituted arylalkyl group, an unsubstituted arylalkylgroup, an unsubstituted aromatic group, a substituted heteroaromaticheterocyclic group, a substituted aralkyl group, an unsubstitutedaralkyl group, a substituted aryloxy group, an unsubstituted aryloxygroup, a substituted alkyloxyl group and an unsubstituted alkyloxylgroup, and wherein M′ represents a substituted or unsubstitutedheteroaromatic ring, wherein the heteroaromatic group is selected fromthe group consisting of a pyridine ring, a pyrimidine ring, a pyrazinering, a triazine ring, an azaindolizine ring, an indolizine ring, animidazole ring, an isoindole ring, an indazole ring, a purine ring, apteridine ring, a β-carboline ring, a naphthyridine ring, a quinoxalinering, a terpyridine ring, a bipyridine ring, an acridine ring, aphenanthroline ring, a phenazine ring, and an imidazopyridine ring, Mand M′ may represent a same ring or different rings, L represents asingle bond, p represents an integer of 1 or 2, q represents an integerof 1, r represents an integer of 0 to 2; and n represents an integerof
 1. 2. A material for organic electroluminescence devices according toclaim 1,wherein p=2 and r=0 in formula (A).
 3. A material for organicelectroluminescence devices according to claim 1, wherein Cz representsa substituted or unsubstituted arylcarbazolyl group.
 4. A material fororganic electroluminescence devices according to claim 3, wherein Czrepresents a substituted or unsubstituted phenylcarbazolyl group.
 5. Amaterial for organic electroluminescence devices according to Claim 3,wherein an aryl portion of the arylcarbazolyl group is substituted withcarbazolyl group.
 6. A material for organic electroluminescence devicesaccording to claim 1,wherein a triplet energy gap of a compoundrepresented by general formula (1) is 2.5 to 3.3 eV.
 7. A material fororganic electroluminescence devices according to claim 1,wherein asinglet energy gap of a compound represented by general formula (1) is2.8 to 3.8 eV.
 8. An organic electroluminescence device comprising ananode, a cathode and an organic thin film layer comprising at least onelayer and disposed between the anode and the cathode, wherein at leastone layer in the organic thin film layer comprises a material fororganic electroluminescence devices described in claim
 1. 9. An organicelectroluminescence device according to claim 8, wherein the materialfor organic electroluminescence devices is an organic host material. 10.An organic electroluminescence device according to claim 8, whichcomprises an inorganic compound layer disposed between at least one ofthe electrodes and the organic thin film layer.
 11. An organicelectroluminescence device according to claim 8, which emits light by amultiplet excitation which is excitation to a triplet state or higher.12. An organic electroluminescence device according to claim 8, whichemits bluish light.
 13. An organic electroluminescence device comprisingan anode, a cathode and an organic thin film layer comprising at leastone layer and disposed between the anode and the cathode, wherein alight emitting layer comprises a material for organicelectroluminescence devices described in claim
 1. 14. An organicelectroluminescence device comprising an anode, a cathode and an organicthin film layer comprising at least one layer and disposed between theanode and the cathode, wherein an electron transporting layer comprisesa material for organic electroluminescence devices described in claim 1.15. An organic electroluminescence device comprising an anode, a cathodeand an organic thin film layer comprising at least one layer disposedbetween the anode and the cathode, wherein a hole transporting layercomprises a material for organic electroluminescence devices describedin claim
 1. 16. A material for organic electroluminescence devicesaccording to claim 1, wherein the heteroaromatic ring for M′ has atleast two nitrogen atoms as its ring members.
 17. A material for organicelectroluminescence devices according to claim 1, wherein thearylcarbazolyl group is N-bonded to A.
 18. The material for organicelectroluminescence devices according to claim 1, wherein the compoundrepresented by formula (1) is at least one selected from the groupconsisting of:


19. The material for organic electroluminescence devices according toclaim 1, wherein the heteroaromatic ring for M′ is selected from thegroup consisting of a pyridine ring, a pyrimidine ring, a triazine ring,an indolizine ring, a β-carboline ring, and an imidazopyridine ring. 20.The material for organic electroluminescence devices according to claim1, wherein the heteroaromatic ring for M′ is selected from the groupconsisting of a pyridine ring and a pyrimidine ring.
 21. The materialfor organic electroluminescence devices according to claim 1, whereinthe arylcarbazolyl group is bonded to A via the carbazolyl portion ofthe arylcarbazolyl group.
 22. The material for organicelectroluminescence according to claim 1, wherein r=1 or
 2. 23. Thematerial for organic electroluminescence devices according to claim 1,wherein p=2.
 24. The material for organic electroluminescence devicesaccording to claim 1, wherein the pyrimidine M is substituted with atleast one group selected from the group consisting of a fluorine atom, amethyl group, a phenyl group, a naphthyl group, a pyridyl group, apyrazyl group, a pyrimidyl group, an adamantyl group, a benzyl group, acyano group and a silyl group.
 25. The material for organicelectroluminescence devices according to claim 1, wherein M issubstituted with an unsubstituted aromatic group selected from the groupconsisting of a phenyl group, a naphthyl group, a biphenyl group, and anunsubstituted heteroaromatic heterocyclic group.